I basically did every possible tune up available on my auto, ngk plugs, pcv, fuel & air filter,cleaned TB and IACV, used alot of fuel system cleaner, engine and tranny oils changed regularly, both o2 sensors on ypipe replaced, knock sensor replaced...I am not getting and ecu codes, I get about 8-12 mpg 50/50 highway/city driving...i know i am not the only one on the org with this problem as i have read alot of threads about these problems...Could coil packs going bad?i have no idea, with the rising gas prices Can someone shed some insight ?!?

Edit: Yes i do check my tire PSI

 

injectors bad?

 

I'm in the same club that you're in.

 

I def know this is affecting countless max owners, every possible thing has been done i dont know what it could be...My injectors sound fine i put a screwdriver to one end and listen on the other end and they are fine no ecu codes...there must be something that we are overlooking...

 

Well everyone knows maxima fuel gauges are **** so maybe try buying a small external fuel gauge and see if you notice any changes.

 

I have a 98 max and I have the same problem. The only thing I've been able to relate it to is either changing the fuel filter or physically having the injectors cleaned and stop flooring it in the city ! I get about 10 MPG and I'm crying too about the gas prices! Both Knock and oxygen sensor were just changed and hardly any improvement.

 

o2 sensor?

 

Egr most likely. I have all the same crap you all do. I did everything I possibly could, replaced everything. Only thing that's left is the egr. I thought it was my injectors but they all read 12ohms.

 

How are you all checking your mileage? I have noticed my trip odometer sticking in the past. Try to compare what you think you have gone to actual miles on the odometer. I have never cleaned my EGR at 160,000 and get 25 MPG average per tank.

 

it is so funny because there are so many threads about cleaning the EGR valve and i still do not know where it is on my 96...I hope that will solve our problems, but that being responsible for 10mpg lost i doubt it but...lets hope so

 

http://forums.maxima.org/showthread....30#post2910030

this may be offtopic, BUT, i just pulled up a code (0306) EGR BPT valve...

I dont get very good gas mileage either, like around 200 MPG for a lil under a full tank... a lil more city and freeway miles, but still..

Now that you mentioned the EGR, i dont know what this is, and im scared to pull it out cause i dont really know what im doin...can anyone explain to me what i should do to clean this? possibly replace a hose to get rid of the code?

I need help on this, and if i fix the code, ill check my millage and let you guys know if my fuel economy is better after replacing or cleaning the EGR...

HELP!!! btw look at my other posts on this...

 

Yeah check injectors, and also check injector connectors, could be corroded. Also, you might check to make sure your fuel pressure is in spec (just a thought). Finally, check all your cylinders for proper compression. In my old 90 300ZX, three of my six cylinders were under spec for compression (120 compared to 180) and I'm pretty sure that was the cause for my crappy mileage on it (got ~15).